Numerous airport visual aids are available to provide information and guidance to pilots maneuvering on airports. These aids may consist of single units or complex systems composed of many parts. Often visual aids have different performance requirements and configurations, but may share common installation procedures. For example, installation procedures for in-pavement lighting systems are essentially the same, yet the lighting systems may perform different functions. Examples of airport visual aids include runway centerline and edge lighting systems, taxiway centerline and edge lighting systems, touchdown zone lighting systems, runway guard lights, stop bars, threshold lights, and clearance bars.
There are generally two types of circuits used to power airport lighting systems, namely, series powered circuits and parallel powered circuits. Series powered circuits are recommended for most lighting systems, particularly high intensity runway lights (HIRLs), medium intensity runway lights (MIRLs), and medium intensity taxiway lights (MITLs). Parallel circuits are often used to power low intensity runway lights (LIRLs) and various visual landing aids such as precision approach path indicators (PAPIs) and runway end identifier lights (REILs), but may also be used with MIRLs or MITLs.
Series powered airport lighting circuits are more commonly used than parallel circuits and are powered by constant current regulators (CCRs). In a series powered airport lighting circuit, a series plug cutout (SPC) may be is installed at the CCR output through which a airfield series circuit passes, and to the airfield series loop which supports the lighting components of the designated lighting system. The SPC is used to isolate the CCR output from the airfield series loop for maintenance personnel safety, and when the plug cut out is removed shorts the series loop and the CCR. The CCR and the associated SPC servicing each airfield series loop are typically housed in a vault, and are controlled locally, such as with a control panel, or remotely, such as from a remote monitoring station and control panel/system.
CCRs must undergo periodic servicing in the nature of maintenance, repair, or replacement. A CCR must be deactivated before it may be serviced. When a CCR is deactivated, the series loop it services is also deactivated, which requires the area of the airfield serviced by the lighting components associated with the series loop to be closed until the airfield series circuit is re-activated. Closing portions of airport airfields for the purpose of servicing CCRs is costly, inconvenient, and unsafe, particularly at high-traffic airports. Accordingly, what is needed is a system and method whereby a CCR may be periodically taken offline for servicing purposes without rendering inoperative the series loop it services.